1. Field of Invention
The invention is related to a color laser printer having a photosensitive member and an intermediate transfer member.
2. Description of Related Art
A color laser printer for forming a color image is known. In a color laser printer, an intermediate transfer member bears a color image that is formed by overlapping visible images of each color and the color image on the intermediate transfer member is transferred to a paper. The color laser printer has a plurality of developing devices each of which stores toner of a different color, a photosensitive member bearing a visible image of each color that is developed by toner supplied from each developing device and the intermediate transfer member bearing the visible images of each color in an overlapped condition.
After the visible images formed on a photosensitive belt for each color are transferred to the intermediate transfer member, a small amount of toner remains on the photosensitive member. As shown in Japanese Patent Laid-Open Publication No. 2-79890, a cleaning roller is provided for removing the remaining toner. The cleaning roller is a roller of silicone rubber. The cleaning roller is arranged on a downstream side from a contact position where the photosensitive member contacts the intermediate transfer member and also on an upstream side from the developing device. The cleaning roller contacts a surface of the photosensitive member and captures the remaining toner. Thus, there is no remaining toner to affect the visible image that is next formed and color mixture is prevented.
However, because the cleaning roller always contacts the photosensitive member, the cleaning roller remains in contact with a same position of the photosensitive belt while the photosensitive member is stopped. If the condition is maintained for a long time, the contact portion of the photosensitive member with the cleaning roller is stained. A visible image that will be formed on the contact portion is deteriorated and the color image may be deteriorated.
If the cleaning roller is structured so as to contact and separate from the photosensitive member and the cleaning roller separates from the photosensitive member while the photosensitive member stops, the above-described problem can be prevented. However, when the cleaning roller contacts and separates from the photosensitive member, the surface of the photosensitive member may be blurred by toner. Further, a complicated structure is necessary so that the cleaning roller contacts and separates from the photosensitive member and the cost may be increased.
An object of the invention is to prevent deterioration of an image due to contact of a cleaning roller and a photosensitive member when an image forming operation stops.
In an image forming apparatus of the invention, a photosensitive member has an image region and a no-image region and a developing device is arranged corresponding to the photosensitive member and supplies developer to the image region of the photosensitive member. The image forming apparatus has a cleaning roller arranged corresponding to the photosensitive member for capturing the developer on a surface of the photosensitive member by contacting the surface of the photosensitive member. The image forming apparatus has a controller for stopping the photosensitive member at a position where the no-image region of the photosensitive member contacts the cleaning roller.
Stop control means stops the photosensitive member in a position so the no-image region of the photosensitive member contacts the cleaning roller. Even if the image forming apparatus is left for a long time in that condition, toner is supplied to the image region of the photosensitive member and toner is not supplied to the no-image region in forming an image. That is, even if the no-image region of the photosensitive member is stained by contact with the cleaning roller, a subsequent image formed is not affected by the stain.